In the conveyance of a chip component such as a multilayer ceramic capacitor in the course of a manufacturing process, there arises a case where it is necessary to transfer the chip component from a conveyance line at a first given height to another conveyance line at a second given height lower than the first given height. To cope with such a case, as shown in FIG. 10, there has been known a device where a plurality of conveyance belts 101, 102, 103 are vertically arranged in multiple stages, a chip component C on the conveyance belt 101 at the uppermost stage is made to fall on the conveyance belt 102 in the next stage and, thereafter, the chip component C is made to sequentially fall on the conveyance belts in lower stages so that it is possible to convey the chip component C by reducing a fall impact on the chip component C stage by stage. Since a crack or chipping easily occurs in a chip component such as a multilayer ceramic capacitor due to a fall impact and hence, it is necessary to control a fall height H of a chip component per one stage within an allowable fall distance.
For example, when a multilayer ceramic capacitor having a rectangular parallelepiped shape of 0.5×0.5×1.0 mm makes a free fall from a height of 1 m, a falling speed is accelerated to approximately 4 m/s. When the chip component is made to collide with a rigid plate (for example, a ceramic plate) at such a speed, it is confirmed by an experiment that the chip component suffers damage such as a crack or chipping with probability of 30% or more. On the other hand, when the fall height is set to 50 mm, probability that the chip component suffers a crack or chipping is almost 0%. In this case, a falling speed is 1 m/s. From the above, an allowable fall distance of this chip component is 50 mm, and an allowable impact speed is 1 m/s. Accordingly, in a case where a chip component falls from a height exceeding 50 mm, it is necessary to take any suitable measure to reduce a fall impact.
When a chip component is made to fall on a soft elastic mat such as urethane or a sponge, the mat absorbs an impact generated by the chip component and hence, it is possible to avoid a breakage or a damage of the chip component. However, when a large number of chip components are continuously made to fall on the mat, the chip component which falls first and the chip component which falls subsequently collide with each other so that a crack or chipping occurs in the chip component due to the impact. In case of the previously-mentioned chip component having a size of 0.5×0.5×1.0 mm, the allowable relative speed at which a crack or a damage does not occur due to a collision between the chip components is approximately 2 m/s.
In the previously-mentioned conveyance apparatus which uses the belts, to prevent the chip component which falls subsequently from colliding with the chip component which falls first, it is necessary to adjust conveyance speeds of the belts. Accordingly, it is necessary to constantly drive the plurality of belts so that power energy is also increased. Further, in the case where a large number of chip components are made to fall at a stroke, there is a possibility that the occurrence of collision cannot be solved even when conveyance speeds of the belts are increased.
JP-A-2007-153576 discloses a chute apparatus of a conveyor which aims at the reduction of a fall impact. The chute apparatus includes conveyance passages arranged in plural stages in a height direction, and with respect to the respective conveyance passages vertically arranged adjacently to each other, an upstream-side end portion of the conveyance passage positioned on a lower side is rotatably connected to a downstream end portion of the conveyance passage positioned on an upper side. The chute apparatus further includes: a fall speed reducing apparatus where respective conveyance passages are inclined downward from an upstream side to a downstream side in a free state; and a wire which is provided to the conveyance passage in the lowermost stage, and performs the height adjustment of the fall speed reducing apparatus by elevating or lowering the conveyance passage.
However, the chute apparatus described in JPA-2007-153576 has drawbacks including the following drawbacks (1) to (3).
(1) It is necessary to provide the conveyance passages having considerably large lengths to acquire the sufficient reduction of a fall impact.
(2) It takes a considerable time to move the chip components since the chip components are made to fall while being moved in a zigzag manner.
(3) It is necessary to rotatably connect the plurality of conveyance passages by way of a hinge shaft and hence, the apparatus becomes large-sized and complicated.